From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05FE8C433E0 for ; Thu, 7 Jan 2021 18:17:05 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A7EB4233FD for ; Thu, 7 Jan 2021 18:17:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A7EB4233FD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=UkNBAxypi+gholUpSk2EM9wElrpRsu8bjedoF84sAwM=; b=ERTVFNweGcKd5cT5p27J/pSyo 4omVFYT6+jmFnHX8aGyxJyWdMjDpqIOS37un7w2ErujguVORCakLHte3Itl93pxVYH8xrvUl4BduW dHAE/Ra4fhqJCK9vlRq7XngF8x99qrfPeTq9Vh0y+bHLZSzdeairzW2uscWmjlKp0ojyDwobNDntD TOfZuT9oOPC8GuF1bYFnrg/cjlxD6j1VXQBi1i53UsALAr6nrZlnm2csr3CYV4zfbU9fnggKwfeyx l9blN2NRlAZq48KK4FyB67b1YzBAkToPo5D/ZuA2YhqVO36yHC0zAzm5rTEoukmCAGZOosP9khm1A Q8eO0rIlA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kxZnl-00027q-M8; Thu, 07 Jan 2021 18:14:25 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kxZnj-00027R-Ka for linux-arm-kernel@lists.infradead.org; Thu, 07 Jan 2021 18:14:24 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6E3A723370; Thu, 7 Jan 2021 18:14:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610043262; bh=/MSHsglIZApAzg6qbqUiSyTvVDKCfmIDw61iXbf+eFQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Gy7+A3tQLG/rL1UITFTM/OPgcLaxU5kxFTvdkt55Z852aRGwzDd6nHHm8v/LDjDYG C87mxApN9s3kSyhSWpUxeRlZBLQ+qHycoQ6I0UTqZRNMQr4xFD9VWLGF5buO/qCFzN /rtWCqvZ0xHf7YTwlSeZPKmrMwY8mD4FtG1YsFI/aQMSy6IoMbTgdEM6kDfkgPS9su nmSh3kbkqjA1mig6QwvjfkfLZ0VEIiXdw8AoUAXdcjUQ5xyqeZAm+JIB0wL0NLW5Un jdNC7cx1iOR3CZr4SPHXqvC2Y3ADLCEoU3095X5WnNfOxqyOQ0wBSDByha5/z2af7h OUDIzcCn2RXVA== Date: Thu, 7 Jan 2021 18:14:17 +0000 From: Will Deacon To: Jeremy Linton Subject: Re: [PATCH] arm64: PCI: Enable SMC conduit Message-ID: <20210107181416.GA3536@willie-the-truck> References: <20210105045735.1709825-1-jeremy.linton@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210105045735.1709825-1-jeremy.linton@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210107_131423_777932_46C6A7EE X-CRM114-Status: GOOD ( 13.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, lorenzo.pieralisi@arm.com, linux-pci@vger.kernel.org, sudeep.holla@arm.com, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, bhelgaas@google.com, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Jan 04, 2021 at 10:57:35PM -0600, Jeremy Linton wrote: > Given that most arm64 platform's PCI implementations needs quirks > to deal with problematic config accesses, this is a good place to > apply a firmware abstraction. The ARM PCI SMMCCC spec details a > standard SMC conduit designed to provide a simple PCI config > accessor. This specification enhances the existing ACPI/PCI > abstraction and expects power, config, etc functionality is handled > by the platform. It also is very explicit that the resulting config > space registers must behave as is specified by the pci specification. > > Lets hook the normal ACPI/PCI config path, and when we detect > missing MADT data, attempt to probe the SMC conduit. If the conduit > exists and responds for the requested segment number (provided by the > ACPI namespace) attach a custom pci_ecam_ops which redirects > all config read/write requests to the firmware. > > This patch is based on the Arm PCI Config space access document @ > https://developer.arm.com/documentation/den0115/latest Why does firmware need to be involved with this at all? Can't we just quirk Linux when these broken designs show up in production? We'll need to modify Linux _anyway_ when the firmware interface isn't implemented correctly... Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel